Effects of SiC, SiO₂ and CNTs Nanoadditives on the Properties of Porous Alumina-Zirconia Ceramics Produced by a Hybrid Freeze Casting-Space Holder Method

Abstract

Highly porous alumina-zirconia ceramics were produced by adding space-holder materials during freeze casting. To increase the strength of porous ceramics, different amounts of nanoadditives (silicon carbide-SiC, silica-SiO2, and multi-wall carbon nanotubes-CNTs) were added. Space-holder materials were removed by preheating, and solid samples were produced by sintering. Up to 68% porosity was achieved when 40% space-holder was added to the solid load of slurry. Wall thicknesses between pores were more uniform and thinner when nanoadditives were added. Compressive tests revealed that SiC nanoparticles increased the strength more than other nanoadditives, and this was attributed to formation of an alumina-SiC phase and a uniform distribution of SiC nanoparticles. Results indicated that by including 20% space-holder materials and 15% SiC nanoparticles, the density decreases by 33.8% while maintaining a compressive strength of 132.5 MPa and porosity of 43.4%. Relatively low thermal conductivities, less than 3.5 W/K-m, were measured for samples with SiC nanoparticles.

Department(s)

Materials Science and Engineering

Research Center/Lab(s)

Center for High Performance Computing Research

Keywords and Phrases

Alumina; Carbon; Carbon Nanotubes; Ceramic Materials; Compressive Strength; Multiwalled Carbon Nanotubes (MWCN); Nanoparticles; Porosity; Porous Silicon; Silicon Carbide; Silicon Oxides; Sintering; Yarn; Zirconia; Alumina-Zirconia; Freeze Casting; Nanoadditives; Porous Ceramics; Space Holders; Casting

International Standard Serial Number (ISSN)

0955-2219

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2017 Elsevier Ltd, All rights reserved.

Publication Date

01 Apr 2017

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